Root Drugs: Rauwolfia and Fagara Roots PDF

# ROOT DRUGS: Rauwolfia and Fagara roots ## U. I. Olayemi (M. Sc. ; B.Pharm. Ife) Department of Pharmacognosy, Faculty of Pharmacy, O. A. U. Ile-Ife. # Rauwolfia: Botanical definition - Rauwolfia consists of the dried rhizome and roots of *Rauwolfia serpentina* L. Benth. ex Kurz. (*Apocynaceae*)...

# ROOT DRUGS: Rauwolfia and Fagara roots ## U. I. Olayemi (M. Sc. ; B.Pharm. Ife) Department of Pharmacognosy, Faculty of Pharmacy, O. A. U. Ile-Ife. # Rauwolfia: Botanical definition - Rauwolfia consists of the dried rhizome and roots of *Rauwolfia serpentina* L. Benth. ex Kurz. (*Apocynaceae*) - It is a small shrub found in India, Pakistan, Burma, Thailand, and Java. # Rauwolfia: Collection and Preparation - Rauwolfia is collected mainly from wild plants. - During collection, some roots must be left in the ground for the plant to regenerate. - After collection the drug is cut transversely and dried. - Cultivation of *Rauwolfia* by nodal and cell culture is being encouraged for the following reasons: 1. Wild plants are being depleted 2. Root collection is destructive 3. *Rauwolfia* has low seed viability 4. *Rauwolfia* is an endangered species # Rauwolfia: macroscopy - Roots are rarely branched - The bark of older pieces of root readily falls off leaving patches of exposed wood. - Longitudinal wrinkles and ridges are found on young and old pieces respectively - Rhizomes differ from the root by a small central pith and some occasional attached aerial stems - Shape: cylindrical or slightly tapering tortuous pieces - Size: 2-10 cm long and 5-22mm in diameter - Colour: greyish yellow or brown - Fracture: short - Odour: slight, decreases with age - Taste: bitter # Rauwolfia: microscopy - The cork is divided into 2-8 zones where smaller suberized unlignified cells alternate with larger lignified cells. - The secondary cortex is parenchymatous with starch. - The phloem is parenchymatous with sieve tubes and calcium oxalate crystals or prisms. - Sclerenchyma is absent in the phloem ( a distinction from other species e.g. *R. vomitoria*). - The xylem is totally lignified, with 3-6 growth rings. - Medullary rays contain starch and alternate with rays of the secondary xylem. - Secondary xylem consists of vessels, fibers, and parenchyma. - The vessels are ≤ 57 µm in diameter ( a distinction from other species e.g. *R. vomitoria* vessels ≤ 180 µm). # Rauwolfia: chemical constituents/uses - *Rauwolfia* contains 0.7-2.4 % of alkaloids which constitutes at least 40 different alkaloids. - Geographical source influences alkaloidal content ( India and Pakistan are preferred sources) - Important alkaloids include: 1. **Reserpine**: hypertension and mental disorders 2. **Rescinnamine**: hypertension 3. **Ajmaline**: cardiac arrhythmias 4. **Ajmalicine**: blood circulatory diseases # <br> The picture shows the chemical structure of **Reserpine**. # Rauwolfia: Allied drugs - 86 species of *Rauwolfia* have been identified many of which are used in the adulteration of *R. serpentina*. - Allied drugs include *R. vomitoria* and *R. tetraphylla*. # Assignment and Further reading - What diagnostic features can be used to distinguish *R. serpentina* from its allied drugs? - Further reading: Trease and Evans. *Pharmacognosy*. 15th Edition. Pages 379-382. # Fagara root: Botanical definition - Fagara root is the dried root of *Zanthoxylum zanthoxyloides* Waterman and other species of *Zanthoxylum* (*Rutaceae*) - Synonym: *Fagara zanthoxyloides* Lam. - Yoruba name: Orin ata / *Igi ata* - It is a small tree 6-12 m high with many hooked thorns (about 12 mm in length) at the base of the stem. # Fagara root: macroscopy and microscopy - Shape: cylindrical and tortuous with attached rootlets - Colour: yellow - Taste: peppery and tingling - Cork layer consists of alternate layers of lignified and unlignified cells - Pericyclic fibers are present but less abundant and vessels are numerous. # Fagara root: Active chemical constituents/Pharmacological activities - The major alkaloids are: 1. **Fagaronine**: Antimalarial activity 2. **Berberine**: Antimicrobial activity 3. **Chelerythrine**: Antimicrobial activity - Major acids include 4. **Para-hydroxy benzoic acid**: Anti-sickling activity 5. **2-hydroxymethylbenzoic acid**: Anti-sickling activity 6. **Vanillic acid**: Anti-sickling activity - Fagara root is used traditionally as a chewing stick to brush the teeth.